Transmission for a motor vehicle

ABSTRACT

A multi-speed transmission for a motor vehicle includes a housing, a drive shaft, an output shaft, and at least four planetary gear sets, whereas each of the planetary gear sets comprises one sun gear, at least one planet, one planetary carrier and one ring gear. Several shift elements are provided in the form of at least four clutches and at least two brakes. The drive shaft is connectable through the third clutch to the first brake and to the sun gear of the first planetary gear set and to the sun gear of the second planetary gear set. The ring gear of the first planetary gear set is connected to the planetary carrier of the fourth planetary gear set. The planetary carrier of the fourth planetary gear set is connectable through the fourth clutch to the drive shaft. The sun gear of the fourth planetary gear set is connected to the housing. The second brake is connected to the planetary carrier of the first planetary gear set.

FIELD OF THE INVENTION

The invention relates to a transmission, in particular a multi-speedtransmission for a motor vehicle, having a housing, a drive shaft, anoutput shaft, at least four planetary gear sets, whereas each of theplanetary gear sets comprises one sun gear, at least one planet, oneplanetary carrier and one ring gear. The transmission includes severalshift elements in the form of at least four clutches and at least twobrakes.

Such transmissions are known, for example, from WO 2012/052284 A1. In WO2012/052284 A1, a multi-speed transmission with six forward gears andone reverse gear is shown, which comprises four planetary gear sets,seven rotatable shafts and five shift elements. The sun gear of thefirst planetary gear set is connected to the sixth shaft, which isattachable through a first brake to the housing of the transmission. Thebar of the first planetary gear set is connected to the fifth shaft,which is connected to the sun gear of the second planetary gear set andis attachable through a second brake to the housing. The drive shaft isconnected to the ring gear of the first planetary gear set and to thesun gear of the third planetary gear set and is detachably connectablethrough a clutch to the seventh shaft connected to the bar of the thirdplanetary gear set and the ring gear of the fourth planetary gear set.The fourth shaft is connected to the ring gear of the third planetarygear set and to the bar of the second planetary gear set and isconnectable through a third brake to the housing. The output shaft isconnected to the ring gear of the second planetary gear set and to thebar of the fourth planetary gear set. The sun gear of the fourthplanetary gear set is connected to the third shaft, which is attachablethrough a fourth brake to the housing.

The disadvantage here is that internal shift elements, such asmulti-disk clutches or brakes, are hydraulically actuated. Thishydraulic actuation leads to high hydraulic losses. In order to avoidsuch actuation losses, providing electromechanical or electro-hydraulicactuation has been proposed. In turn, the disadvantage here is that theshift elements, primarily clutches, are difficult to access, inparticular if good gearing efficiency and low component stresses withlow construction costs are desired.

SUMMARY OF THE INVENTION

As such, a task of the present invention is to provide a transmissionfor a motor vehicle, which has a high degree of efficiency, lowcomponent stress and low construction costs. Moreover, it is a task ofthe present invention to provide a transmission for a motor vehicle thatfeatures good accessibility for its shift elements from the outside. Anadditional task of the present invention is to provide an alternativetransmission for a motor vehicle. Additional objects and advantages ofthe invention will be set forth in part in the following description, ormay be obvious from the description, or may be learned through practiceof the invention.

The present invention solves the task with a transmission, in particulara multi-speed transmission for a motor vehicle, having a housing, adrive shaft, an output shaft, and at least four planetary gear sets,whereas each of the planetary gear sets comprises one sun gear, at leastone planet, one planetary carrier and one ring gear. Several shiftelements are provided in the form of at least four clutches and at leasttwo brakes. The drive shaft is connectable through the third clutch tothe first brake and to the sun gear of the first planetary gear set andto the sun gear of the second planetary gear set. The ring gear of thefirst planetary gear set is connected to the planetary carrier of thefourth planetary gear set. The planetary carrier of the fourth planetarygear set is connectable through the fourth clutch to the drive shaft.The sun gear of the fourth planetary gear set is connected to thehousing. The second brake is connected to the planetary carrier of thefirst planetary gear set.

The invention also solves the task with a motor vehicle, in particularfor a passenger car or a truck, with a transmission in accordance withthe invention.

The invention also solves the task with a method for operating atransmission in accordance with the invention having two brakes and fourclutches. A first gear is realized by means of an open first brake, alocked second brake, an open first clutch, a locked second clutch, anopen third clutch and a locked fourth clutch. A second gear is formed bymeans of a locked first brake, an open second brake, an open firstclutch, a locked second clutch, an open third clutch and a locked fourthclutch. A third gear is formed by means of an open first brake, an opensecond brake, an open first clutch, a locked second clutch, a lockedthird clutch and a locked fourth clutch. A fourth gear is formed bymeans of an open first brake, an open second brake, a locked firstclutch, an open second clutch, a locked third clutch and a locked fourthclutch, or by means of an open first brake, a locked second brake, alocked first clutch, an open second clutch, an open third clutch and alocked fourth clutch, or is formed by means of a locked first brake, anopen second brake, a locked first clutch, an open second clutch, an openthird clutch and a locked fourth clutch, or is formed by means of anopen first brake, an open second brake, a locked first clutch a lockedsecond clutch, an open third clutch and a locked fourth clutch. A fifthgear is formed by means of an open first brake, an open second brake, alocked first clutch, a locked second clutch, a locked third clutch andan open fourth clutch. A sixth gear is formed by means of a locked firstbrake, an open second brake, a locked first clutch, a locked secondclutch, an open third clutch and an open fourth clutch. A seventh gearis formed by means of an open first brake, a locked second brake, alocked first clutch, a locked second clutch, an open third clutch and anopen fourth clutch. An eighth gear is formed by means of a locked firstbrake, a locked second brake, a locked first clutch, an open secondclutch, an open third clutch and an open fourth clutch. A ninth gear isformed by means of an open first brake, a locked second brake, a lockedfirst clutch, an open second clutch, a locked third clutch and an openfourth clutch. A reverse gear is formed by means of an open first brake,a locked second brake, an open first clutch, an open second clutch, alocked third clutch and a locked fourth clutch.

One of the advantages obtained thereby is that, in this manner, a goodaccessibility of all shift elements is ensured. In addition, theconstruction costs are low, which means lower costs and weight of thetransmission.

It is particularly preferable that, through the drive shaft, a torque ora rotational movement of a drive shaft, for example an internalcombustion engine, is introduced into the transmission. In a preferredmanner, a start-up element, such as a hydrodynamic torque converter or afluid clutch, is located between the drive shaft and the output shaft.

In the following, a “shaft” is not solely understood as an exemplarycylindrical, rotatably mounted machine element for the transfer oftorques, but is also understood as a general connection element, whichconnects individual components or elements to each other, in particularconnection elements that connect several elements to each other in atorque-proof manner.

In particular, two elements are described as connected to each other ifthere is a fixed (in particular, a torque-proof) connection between theelements. In particular, such connected elements rotate with the samerotational speed.

Furthermore, two elements are described as connectable if there is adetachable connection between such elements. In particular, suchelements rotate with the same rotational speed if the connection exists.

The various components and elements of the specified invention may beconnected to each other through a shaft or a connection element, or alsodirectly, for example by means of a welded connection, crimpingconnection or another connection.

In the description, in particular in the claims, “clutch” is preferablyunderstood as a shift element that, depending on the operating state,allows a relative movement between two components or represents aconnection for transferring torque. “Relative motion” is understood (forexample) as a rotation of two components, whereas the rotational speedof the first component and the rotational speed of the second componentare different from one another. Moreover, the rotation of only one ofthe two components is possible, while the other component is at astandstill or is rotating in the opposite direction.

In the following, a “non-actuated clutch” is understood as an openclutch. This means that a relative movement between the two componentsis possible. With an actuated or locked clutch, the two componentsrotate accordingly at the same rotational speed in the same direction.

In the description, in particular in the claims, a “brake” is understoodas a shift element that is connected on one side to a stationaryelement, such as a housing, and on the other side to a rotatableelement.

In the following, a “non-actuated brake” is understood as an open brake.This means that the rotating component is freely rotatable; that is, thebrake preferably has no influence on the rotational speed of therotating component. With an actuated or locked brake, there is areduction in the rotational speed of the rotatable component up to astandstill; that is, a firm connection between the rotatable element andthe stationary element can be produced. In this context, “element” and“component” are equivalent.

As a general rule, the use of shift elements that are locked in anon-actuated state and open in an actuated state is also possible.Accordingly, the allocations between function and shifting state of theshifting states described above are understood in reverse order. Withthe following embodiments on the basis of the figures, an arrangement inwhich an actuated shift element is locked and a non-actuated shiftelement is open is initially used as the basis.

A planetary gear set comprises one sun gear, one planetary carrier orbar, as the case may be, and one ring gear. Planetary gears or planetsthat mesh with the toothing of the ring gear and/or with the toothing ofthe sun gear are rotatably mounted on the planetary carrier or the bar,respectively.

In the following, a negative planetary gear set describes a planetarygear set with a planetary carrier on which the planetary gears arerotatably mounted, with one sun gear and one ring gear, whereas thetoothing of at least one of the planetary gears meshes with both thetoothing of the sun gear and with the toothing of the ring gear, bywhich the ring gear and the sun gear rotate in opposite directions, ifthe sun gear rotates with a fixed planetary carrier.

A positive planetary gear set differs from the negative planetary gearset just described in that the positive planetary gear set featuresinner and outer planetary gears, which are rotatably mounted on theplanetary carrier. Thereby, the toothing of the inner planetary gearsmeshes, on the one hand, with the toothing of the sun gear and, on theother hand, with the toothing of the outer planetary gears. The toothingof the outer planetary gears also meshes with the toothing of the ringgear. This has the consequence that, with a fixed planetary carrier, thering gear and the sun gear rotate in the same direction of rotation.

A particularly compact transmission can be realized through the use ofplanetary gear sets, by which a high degree of freedom in thearrangement of the transmission in the vehicle is achieved.

“Elements of a planetary gear set” are understood in particular as thesun gear, the ring gear, the planetary carrier or bar, respectively, andthe planetary carrier or planets, respectively, of the planetary gearset.

It is particularly preferable that the shift elements are able to beactuated selectively, thus individually and in line with demand, bywhich different gears can be realized through different transmissionratio relationships between the drive shaft and the drive shaft. Thehigher the number of gears, the finer a gear shifting can be realizedwith a large gear spread, and thus, for example, an internal combustionengine of a motor vehicle can be operated in an optimal rotational speedrange and thus as efficiently as possible. At the same time, thiscontributes to increased driving comfort, since the internal combustionengine preferably can be operated at a low rotational speed level. Thus,for example, noise emissions that arise through the operation of theinternal combustion engine are reduced.

The term “front-transverse arrangement” is understood as an arrangementwith which the drive shaft, for example an internal combustion engine,is installed transversely to a direction of travel in a motor vehicle,and preferably the wheels of a front axle can be driven by the driveshaft or the transmission, as the case may be. Furthermore, the shiftelements may be formed in such a manner that energy is required for achange of the shifting state of the shift elements, but not formaintaining the shifting state itself.

For this purpose, use of electromechanical shift elements orelectromagnetic shift elements are advantageous. Particularly whencompared to conventional hydraulically actuated shift elements, they arecharacterized by a particularly low and efficient energy demand, sincethey can be operated nearly loss-free. In addition, in an advantageousmanner, permanently holding a control pressure for the actuation of the(for example) conventional hydraulic shift elements, and/or permanentlyapplying the shift element in the locked state with the requiredhydraulic pressure, can be avoided. Thereby, additional components suchas a hydraulic pump (for example) may be omitted, to the extent thatthey are solely used for the control and supply of conventionalhydraulically actuated shift elements. If the additional components aresupplied with lubricants by the same hydraulic pump, and not by aseparate lubrication pump, at least this can be dimensioned smaller.Moreover, any leaks at the oil transfer points of the hydraulic circuitthat may arise, particularly with rotating components, are eliminated.It is particularly preferable that this also contributes to increasedefficiency of the transmission in the form of a higher degree ofefficiency.

Upon the use of actuated shift elements in line with demand of the typespecified above, it is particularly advantageous if they are accessiblefrom outside of the planetary gear sets. Among other things, that hasthe advantage that the required shifting energy can be easily fedtransferred to the shift elements. Therefore, the shift elements are,particularly preferably, arranged so that they are easily accessiblefrom the outside. Within the meaning of the shift elements, “easilyaccessible from the outside” means that no additional components arearranged between the housing of the transmission and the shift element,and/or that the shift elements are, particularly preferably, arranged onthe output shaft or on the drive shaft.

In the description, in particular in the claims, the term “bindingability” is preferably understood such that, with a differentgeometrical positioning, the same connection or binding of theinterfaces is ensured, without the individual connection elements orshafts crossing each other.

The term “stationary transmission ratio” is understood as thattransmission ratio that is realized by the transmission ratiorelationship between the sun gear and the ring gear of the respectiveplanetary gear set if the planetary carrier or bar is fixed.

Additional advantageous embodiments, characteristics and advantages ofthe invention are described in the following description.

Advantageously, the planetary gear sets are arranged, in particulargeometrically, behind one another in the transmission. This allows easymanufacturing and the easier accessibility of the planetary gear sets inthe event of maintenance.

Beneficially, the drive shaft is connectable through the first clutch tothe planetary carrier of the third planetary gear set, and the planetarycarrier of the second planetary gear set is connected to the ring gearof the fourth planetary gear set, and the output shaft is connected tothe ring gear of the third planetary gear set. In this manner, on theone hand, power can be flexibly transferred from the drive shaft throughthe first clutch to the third planetary gear set, depending on the need,and then further to the output shaft; on the other hand, the flexibilityof the transmission is further increased with respect to thepresentation of different gears, since the second and fourth planetarygear sets are directly connected to each other.

Advantageously, the ring gear of the third planetary gear set isconnectable through the first clutch to the output shaft, and the driveshaft is connected to the planetary carrier of the third planetary gearset. Thus, the third planetary gear set can be coupled in a flexiblemanner to the output shaft and can be directly subjected to power andtorque from the drive shaft

Beneficially, the ring gear of the fourth planetary gear set isconnectable through the first clutch to the sun gear of the thirdplanetary gear set. Thus, planetary gear sets arranged in thetransmission (in particular, behind one another) are connected to eachother, in a flexible manner, depending on the need.

Advantageously, the planetary carrier of the second planetary gear setis connectable through the second clutch to the ring gear of the fourthplanetary gear set, and the drive shaft is connected to the ring gear ofthe second planetary gear set, or the drive shaft is connectable throughthe second clutch to the ring gear of the second planetary gear set, andthe planetary carrier of the second planetary gear set is connected tothe ring gear of the fourth planetary gear set. In this manner, eithertwo planetary gear sets that are not directly arranged behind oneanother are coupled with each other in a flexible manner, or the driveshaft may be coupled in a flexible manner with the second planetary gearset and, through this, also with the fourth planetary gear set.

Additional important characteristics and advantages of the inventionarise from the subclaims, from the drawings, and from the associateddescription of the figures on the basis of the drawings.

It is understood that the characteristics specified above and thecharacteristics that are still to be described below are usable not onlyin the indicated combination, but also in other combinations or alone,without leaving the framework of the present invention.

Preferred designs and embodiments of the invention are presented in thedrawings and are described more specifically in the followingdescription, whereas the same reference signs refer to identical orsimilar or functionally identical components or elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The following are shown, each in schematic form:

FIG. 1 is a transmission in accordance with a first embodiment of thepresent invention;

FIG. 2 is a shifting matrix for a transmission in accordance with thefirst embodiment of the present invention;

FIG. 3 is a transmission in accordance with a second embodiment of thepresent invention;

FIG. 4 is a transmission in accordance with a third embodiment of thepresent invention;

FIG. 5 is a transmission in accordance with a fourth embodiment of thepresent invention;

FIG. 6 is a transmission in accordance with a fifth embodiment of thepresent invention;

FIG. 7 is a transmission in accordance with a sixth embodiment of thepresent invention;

FIG. 8 is a transmission in accordance with a seventh embodiment of thepresent invention; and

FIG. 9 is a transmission in accordance with an eighth embodiment of thepresent invention.

DETAILED DESCRIPTION

Reference will now be made to embodiments of the invention, one or moreexamples of which are shown in the drawings. Each embodiment is providedby way of explanation of the invention, and not as a limitation of theinvention. For example features illustrated or described as part of oneembodiment can be combined with another embodiment to yield stillanother embodiment. It is intended that the present invention includethese and other modifications and variations to the embodimentsdescribed herein.

FIG. 1 shows a transmission in accordance with a first embodiment of thepresent invention.

In FIG. 1, reference sign 1 designates a multi-speed transmission. Themulti-stage transmission 1 features six shift elements in the form offour clutches K1, K2, K3, K4 and two brakes B1, B2. By means of the fourclutches K1, K2, K3, K4, the drive side can be coupled or connected tothe output side of the transmission for transferring power and torquesthrough shafts and/or the planetary gear sets. For this purpose, thefirst clutch K1, the second clutch K2 and the third clutch K3 areconnected to the drive shaft ANW on the drive side. The first clutch K1is also connected to a first shaft W1, such that, when actuated, thefirst clutch K1 transfers power and torque from the drive shaft ANW tothe first shaft W1. This correspondingly applies for the second clutchK2 and the third clutch K3. Upon locking the second clutch K2, power andtorque are transferred from the drive shaft ANW to the second shaft W2;upon locking the third clutch K3, power and torque are transferred fromthe drive shaft ANW to the third shaft W3.

In the transmission 1, four planetary gear sets GP1, GP2, GP3, GP4 andseven shafts W1, W2, W3, W4, W5, W6 and W7 are also arranged.

Below, the general structure of the first planetary gear set GP1, thesecond planetary gear set GP2, the third planetary gear set GP3 and thefourth planetary gear set GP4 will initially be described. The planetarygear sets GP1, GP2, GP3 and GP4 specified above are constructed in theusual manner, and in each case feature a central sun gear 101, 102, 103,104, which interacts with a planet 111, 112, 113, 114 for the transferof power and torques. The planet 111, 112, 113, 114 is rotatably mountedon a bar/planetary carrier 121, 122, 123, 124. On the radially outerside of the planet 111, 112, 113, 114, a ring gear 131, 132, 133, 134 isarranged, in which the respective planet 111, 112, 113, 114 is engagedfor the transfer of power and torques. The bar or planetary carrier 121,122, 123, 124, as the case may be, is further connected to a shaft. Theindividual reference signs for sun gear, planet, planetary carrier/barand ring gear can be seen in FIG. 1. For the sake of clarity, thereference signs have been omitted in the additional figures.

The seven different shafts W1, W2, W3, W4, W5, W6 and W7 will then bedescribed.

The first shaft W1 connects the first clutch K1 and the bar 123 of thethird planetary gear set GP3. The second shaft W2 connects the secondclutch K2 to the ring gear 132 of the second planetary gear set GP2. Thethird shaft W3 connects the third clutch K3 to the sun gears 101, 102 ofthe first planetary gear set GP1 and the second planetary gear set GP2.Further, the third shaft W3 can be coupled through the first brake B1 tothe housing G. The fourth shaft W4 connects the bar 122 of the secondplanetary gear set GP2, the sun gear 103 of the third planetary gear setGP3 and the ring gear 134 of the fourth planetary gear set GP4. Thefifth shaft W5 connects the ring gear 131 of the first planetary gearset GP1 and the bar 124 of the fourth planetary gear set GP4 and, bymeans of the fourth clutch K4, can be coupled, on the one hand, with theoutput shaft AW and, on the other hand, with the ring gear 133 of thethird planetary gear set GP3. The sixth shaft W6 is firmly arranged onthe housing G and is connected to the sun gear 104 of the fourthplanetary gear set GP4. The seventh shaft W7 is connected to the bar 121of the first planetary gear set GP1, and can be coupled through thesecond brake B2 with the housing G.

FIG. 2 shows a shifting matrix for a transmission in accordance with thefirst embodiment of the present invention.

FIG. 2 presents a shifting matrix for a transmission 1 in accordancewith FIG. 1. Downwards in a vertical direction to this, nine forwardgears, designated with the reference signs V1 to V9, and one reversegear designated with R, are initially shown. Furthermore, threealternative presentations of the fourth forward gear V4, designated withthe reference signs VM^(I), VM^(II) and VM^(III), are shown. Therespective shift elements are shown horizontally, whereas the two brakesB1, B2 and then the four clutches K1, K2, K3 and K4 are initially shown.Furthermore, the respective transmission ratio relationship/ratio i andthe corresponding gear jump/step φ is shown between two consecutivegears/gear steps. In this respect, the respective gear jump is presentedin the shifting matrix between two adjacent gears/gear steps. With eachof the alternative presentations of the fourth forward gear V4, only thetransmission ratios are indicated.

The entries left empty in the shifting matrix, thus, for example, withthe forward gear V1, with the first brake B1 along with the first clutchK1 and the third clutch K3 indicate that the corresponding shift elementor brakes or clutch, as the case may be, is open; i.e., that the shiftelement thereby does not transfer any power or torque from therespective shafts or elements of the transmission attached to the shiftelement or connected to it. An entry in the shifting matrix providedwith a cross designates a correspondingly actuated or locked shiftelement, thus in the shifting matrix, for example, with the forward gearV1, with the brake B2 and with the clutches K2 and K4. To the extent nototherwise described, the shift elements B1, B2, K1, K2, K3, K4 are open.

In order to present (realize) the first forward gear V1 by means of thetransmission 1 in accordance with FIG. 1, the brake B2 and the clutchesK2 and K4 are locked. The transmission ratio relationship i is 4.344. Inorder to present the second forward gear V2, the brake B1 and theclutches K2 and K4 are locked. The transmission ratio relationship i is2.556.

In order to present the third forward gear V3, all of the brakes areopen and the clutches K2, K3 and K4 are locked. The transmission ratiorelationship i is 1.667. In order to present the fourth forward gear V4,all of the brakes are open and the clutch K1 along with the clutches K3and K4 are locked. The transmission ratio relationship i is 1.267.

In order to present the fifth forward gear V5, all of the brakes areopened and the clutches K1, K2 and K3 are locked. The transmission ratiorelationship i is 1.000. In order to present the sixth forward gear V6,the brake B1 and the clutches K1 and K2 are locked. The transmissionratio relationship i is 0.812.

In order to present the seventh forward gear V7, the brake B2 and theclutches K1 and K2 are locked. The transmission ratio relationship i is0.709. In order to present the eighth forward gear V8, all of the brakesB1, B2 are locked, as is the clutch K1. The transmission ratiorelationship i is 0.600.

In order to present the ninth forward gear V9, the brake B2 along withthe clutches K1 and K3 are locked. The transmission ratio relationship iis 0.500. In order to present the reverse gear R, the brake B2 alongwith the clutches K3 and K4 are locked. The transmission ratiorelationship i is −3.352.

With the first alternative presentation VM^(I), the fourth forward gearV4, the brake B2 and the clutches K1 and K4 are locked. The transmissionratio relationship i is 1.267. With the second alternative presentationVM^(II), the brake B1 and the clutches K1 and K4 are locked. Thetransmission ratio relationship i is 1.267. With the third alternativepresentation VM^(III), all of the brakes are opened and the clutches K1,K2 and K4 are locked. The transmission ratio relationship i is 1.267.

The gear jump φ between the first forward gear V1 and the second forwardgear V2 is 1.700, and between the second forward gear V2 and the thirdforward gear V3 is 1.533. The gear jump φ between the third forward gearV3 and the fourth forward gear V4 is 1.316, and between the fourthforward gear V4 and the fifth forward gear V5 is 1.267. The gear jump φbetween the fifth forward gear V5 and the sixth forward gear V6 is1.232, and between the sixth forward gear V6 and the seventh forwardgear V7 is 1.145. The gear jump φ between the seventh forward gear V7and the eighth forward gear V8 amounts 1.181, and between the eighthforward gear V8 and the ninth forward gear V9 is 1.199. The entire gearjump amounts to 8.68.

Thereby, the first planetary gear set GP1 features a stationarytransmission ratio of i₀=−3.352, the second planetary gear set GP2features a stationary transmission ratio of i₀=−1.875, the thirdplanetary gear set GP3 features a stationary transmission ratioi₀=−1.500 and the fourth planetary gear set GP4 features a stationarytransmission ratio of i₀=−1.500.

FIG. 3 shows a transmission in accordance with a second embodiment ofthe present invention.

FIG. 3 shows a transmission 1 in accordance with FIG. 1. In FIG. 3, twoalternative positions A, B for the first clutch K1 can be viewed, withwhich the first clutch K1 can be arranged in a manner effectively equalto the position in accordance with FIG. 1.

The first alternative position A for the first clutch K1 is locatedbetween the ring gear 133 of the third planetary gear set GP3 and thesection of the output shaft AW that is connected to the fourth clutchK4.

The second alternative position B for the first clutch K1 is locatedbetween the sun gear 103 of the third planetary gear set GP3 and thesection of the fourth shaft W4 that connects the bar 122 of the secondplanetary gear set GP2 to the ring gear 134 of the fourth planetary gearset GP4.

FIG. 4 shows a transmission in accordance with a third embodiment of thepresent invention.

FIG. 4 shows a transmission 1 in accordance with FIG. 1. In FIG. 4, analternative position C for the second clutch K2 can be viewed, withwhich the second clutch K2 can be arranged in a manner effectively equalto the position in accordance with FIG. 1.

The alternative position C for the second clutch K2 is located at thefourth shaft W4 between the bar 122 of the second planetary gear set GP2and the section of the fourth shaft W4 that connects the ring gear 134of the fourth planetary gear set GP4 to the sun gear 103 of the thirdplanetary gear set GP3.

FIG. 5 shows a transmission in accordance with a fourth embodiment ofthe present invention.

FIG. 5 essentially shows a transmission 1 in accordance with FIG. 1. Incontrast to the transmission 1 in accordance with FIG. 1, with thetransmission 1 in accordance with FIG. 5, the first clutch K1, nowdesignated with the reference sign K1′, is arranged at the firstalternative position A in accordance with FIG. 3. The first shaft W1 isomitted. The drive shaft ANW is thus directly connected to the bar 123of the third planetary gear set GP3.

FIG. 6 shows a transmission in accordance with a fifth embodiment of thepresent invention.

FIG. 6 essentially shows a transmission 1 in accordance with FIG. 1. Incontrast to the transmission 1 in accordance with FIG. 1, with thetransmission 1 in accordance with FIG. 6, the first clutch K1, nowdesignated with K1″, is arranged at a second alternative position B inaccordance with FIG. 3. The first shaft W1 is omitted. The drive shaftANW is now directly connected to the bar 123 of the third planetary gearset GP3.

FIG. 7 shows a transmission in accordance with a sixth embodiment of thepresent invention.

FIG. 7 essentially shows a transmission 1 in accordance with FIG. 1. Incontrast to the transmission 1 in accordance with FIG. 1, with thetransmission 1 in accordance with FIG. 7, the second clutch K2, nowdesignated with the reference sign K2′, is arranged at the alternativeposition C in accordance with FIG. 4. The second shaft W2 is omitted.The drive shaft ANW is thus directly connected to the ring gear 132 ofthe second planetary gear set GP2.

FIG. 8 shows a transmission in accordance with a seventh embodiment ofthe present invention.

FIG. 8 essentially shows a transmission 1 in accordance with FIG. 1. Incontrast to the transmission 1 in accordance with FIG. 1, with thetransmission 1 in accordance with FIG. 8, the first clutch K1, nowdesignated with the reference sign K1′, is arranged at the firstalternative position A in accordance with FIG. 3 or FIG. 5. In contrastto the transmission 1 in accordance with FIG. 1, with the transmission 1in accordance with FIG. 8, the second clutch K2, now designated with thereference sign K2′, is arranged at the alternative position C inaccordance with FIG. 4 and FIG. 7. The first shaft W1 and the secondshaft W2 are omitted. The drive shaft ANW is now directly connected tothe ring gear 132 of the second planetary gear set GP2 and to the bar123 of the third planetary gear set GP3.

FIG. 9 shows a transmission in accordance with an eighth embodiment ofthe present invention.

FIG. 9 essentially shows a transmission 1 in accordance with FIG. 1. Incontrast to the transmission 1 in accordance with FIG. 1, the firstclutch K1, now designated with the reference sign K1″, is arranged atthe second alternative position B in accordance with FIG. 3 or FIG. 6.Furthermore, in contrast to the transmission 1 in accordance with FIG.1, with the transmission 1 in accordance with FIG. 9, the second clutchK2, now designated with the reference sign K2′, is arranged at thealternative position C in accordance with FIG. 3 or FIG. 7. The firstshaft W1 and the second shaft W2 are omitted. The drive shaft ANW nowinteracts directly with the ring gear 132 of the second planetary gearset GP2 and the bar 123 of the third planetary gear set GP3.

Overall, the transmission 1 in accordance with FIGS. 1 to 9 comprisesfour planetary gear sets GP1, GP2, GP3, GP4, six shift elements B1, B2,K1, K2, K3, K4, whereas the shift elements are designed in the form ofat least four clutches and at least two brakes. Furthermore, a maximumof one fixed housing coupling is present. Finally, two shift elements tobe shifted simultaneously are arranged.

As a start-up element for the transmission 1, a hydrodynamic torqueconverter, a hydrodynamic clutch, an additional start-up clutch, anintegrated start-up clutch or brake and/or an additional electricalmotor can be arranged. An electrical motor or another power source canbe arranged at each of the seven shafts W1 to W7. Moreover, at each ofthe shafts W1 to W7 or each connection element, a freewheel can bearranged for the housing G or for an additional shaft W1, W2, W3, W4,W5, W7. The transmission 1 may be preferentially incorporated into amotor vehicle in standard drive design or in front-transverse design.Frictional-locking or positive-locking shift elements are possible asshift elements. In particular, the second B2 and the second clutch K2along with the fourth clutch K4 may be designed as positive-lockingshift elements, in particular as a claw shift element, which leads tosignificant consumption advantages for a motor vehicle with an internalcombustion engine provided with the transmission.

The transmission has a total of at least nine forward gears and at leastone reverse gear.

In summary, the present invention offers the advantage that lowconstruction costs are required for the transmission, which results inlower manufacturing costs and a lower weight of the transmission. Thetransmission also provides a good transmission ratio sequence, lowabsolute and relative rotational speeds and low planetary set torquesand shift element torques. Moreover, the present invention provides goodgearing efficiency and a very good accessibility of all of the shiftelements, in particular regarding their maintenance.

Although the present invention was described above on the basis ofpreferred embodiments, it is not limited to them, but can be modified inmany ways.

For example, the geometric position/order of the individual planetarygear sets GP1, GP2, GP3, GP4, and the individual shift elements K1, K2,K3, K4, B1, B2, K1′, K1″, K2′ may be freely selected under considerationof the binding ability of the respective transmission elements amongeach other. Individual transmission elements may be arbitrarily movedinto their position within the transmission 1.

It is also possible, taking into account binding ability, to convertindividual or several planetary gear sets formed as negative planetarygear sets into positive planetary gear sets, with the simultaneousexchange of the bar connection and the ring gear connection and anincrease in the stationary transmission ratio by 1.

Modifications and variations can be made to the embodiments illustratedor described herein without departing from the scope and spirit of theinvention as set forth in the appended claims.

REFERENCE SIGNS

-   1 Transmission-   GP1, GP2, GP3, GP4 Planetary gear set-   101, 102, 103, 104 Sun gear-   111, 112, 113, 114 Planetary gear-   121, 122, 123, 124 Bar-   131, 132, 133, 134 Ring gear-   ANW Drive shaft-   AW Output shaft-   B1, B2 Brake-   K1, K2, K3, K4, K1′, K1″, K2′ Clutch-   G Housing-   V1, V2, V3, V4, V5, V6, V7,-   V8, V9, VM^(I), VM^(II), VM^(III), Forward gear-   R Reverse gear-   W1, W2, W3, W4, W5, W6, W7 Shaft-   i Transmission ratio/ratio-   φ Gear jump/step-   A, B, C Position of clutch

The invention claimed is:
 1. A multi-speed transmission (1) for a motorvehicle, comprising: a housing (G); a drive shaft (ANW); an output shaft(AW); at least four planetary gear sets (GP1, GP2, GP3, GP4), whereineach of the planetary gear sets (GP1, GP2, GP3, GP4) further comprises asun gear (101, 102, 103, 104), at least one planet gear (111, 112, 113,114), a planetary carrier (121, 122, 123, 124), and a ring gear (131,132, 133, 134); a plurality of shift elements (K1, K2, K3, K4, B1, B2)comprising at least four clutches (K1, K2, K3, K4) and at least twobrakes (B1, B2); the drive shaft (ANW) connectable through the thirdclutch (K3) to the first brake (B1) and to the sun gear (101) of thefirst planetary gear set (GP1) and to the sun gear (102) of the secondplanetary gear set (GP2); the ring gear (101) of the first planetarygear set (GP1) connected to the planetary carrier (124) of the fourthplanetary gear set (GP4); the planetary carrier (124) of the fourthplanetary gear set (GP4) connectable through the fourth clutch (K4) tothe output shaft (AW); the sun gear (104) of the fourth planetary gearset (GP4) connected to the housing (G); and the second brake (B2)connected to the planetary carrier (121) of the first planetary gear set(GP1).
 2. The transmission according to claim 1, wherein the planetarygear sets (GP1, GP2, GP3, GP4) are arranged geometrically behind oneanother in the transmission (1).
 3. The transmission according to claim1, wherein; the drive shaft (ANW) is connectable through the firstclutch (K1) to the planetary carrier (123) of the third planetary gearset (GP3); the planetary carrier (122) of the second planetary gear set(GP2) is connected to the ring gear (134) of the fourth planetary gearset (GP4); and the output shaft (AW) is connected to the ring gear (133)of the third planetary gear set (GP3).
 4. The transmission according toclaim 1, wherein the ring gear (133) of the third planetary gear set(GP3) is connectable through the first clutch (K1′) to the output shaft(AW), and the drive shaft (ANW) is connected to the planetary carrier(133) of the third planetary gear set (GP3).
 5. The transmissionaccording to claim 1, wherein the ring gear (134) of the third planetarygear set (GP3) is connectable through the first clutch (K1″) to the sungear (103) of the third planetary gear set (GP3).
 6. The transmissionaccording to claim 1, wherein: the planetary carrier (122) of the secondplanetary gear set (GP2) is connectable through the second clutch (K2)to the ring gear (134) of the fourth planetary gear set (GP4); the driveshaft (ANW) is connected to the ring gear (132) of the second planetarygear set (GP2), or the drive shaft (ANW) is connectable through thesecond clutch (K2) to the ring gear (132) of the second planetary gearset (GP2); and the planetary carrier (122) of the second planetary gearset (GP2) is connected to the ring gear (134) of the fourth planetarygear set (GP4).
 7. A Motor vehicle as a passenger car or a truck,comprising the transmission (1) in accordance with claim
 1. 8. Thetransmission according to claim 1, wherein: first gear (V1) is realizedby an open first brake (B1), a locked second brake (B2), an open firstclutch (K1), a locked second clutch (K2), an open third clutch (K3) anda locked fourth clutch (K4); a second gear (V2) is realized by a lockedfirst brake (B1), an open second brake (B2), an open first clutch (K1),a locked second clutch (K2), an open third clutch (K3) and a lockedfourth clutch (K4); a third gear (V3) is realized by an open first brake(B1), an open second brake (B2), an open first clutch (K1), a lockedsecond clutch (K2), a locked third clutch (K3) and a locked fourthclutch (K4); a fourth gear (V4) is realized by one of: an open firstbrake (B1), an open second brake (B2), a locked first clutch (K1), anopen second clutch (K2), a locked third clutch (K3) and a locked fourthclutch (K4); an open first brake (B1), a locked second brake (B2), alocked first clutch (K1), an open second clutch (K2), an open thirdclutch (K3) and a locked fourth clutch (K4); a locked first brake (B1),an open second brake (B2), a locked first clutch (K1), an open secondclutch (K2), an open third clutch (K3) and a locked fourth clutch (K4);or an open first brake (B1), an open second brake (B2), a locked firstclutch (K1), a locked second clutch (K2), an open third clutch (K3) anda locked fourth clutch (K4); a fifth gear (V5) is realized by an openfirst brake (B1), an open second brake (B2), a locked first clutch (K1),a locked second clutch (K2), a locked third clutch (K3) and an openfourth clutch (K4); a sixth gear (V6) is realized by a locked firstbrake (B1), an open second brake (B2), a locked first clutch (K1), alocked second clutch (K2), an open third clutch (K3) and an open fourthclutch (K4); a seventh gear (V7) is realized by an open first brake(B1), a locked second brake (B2), a locked first clutch (K1), a lockedsecond clutch (K2), an open third clutch (K3) and an open fourth clutch(K4); an eighth gear (V8) is realized by means a locked first brake(B1), a locked second brake (B2), a locked first clutch (K1), an opensecond clutch (K2), an open third clutch (K3) and an open fourth clutch(K4); a ninth gear (V9) is realized by a locked second brake (B2), alocked first clutch (K1), an open second clutch (K2), a locked thirdclutch (K3) and an open fourth clutch (K4); and a reverse gear (R) isrealized by an open first brake (B1), a locked second brake (B2), anopen first clutch (K1), an open second clutch (K2), a locked thirdclutch (K3) and a locked fourth clutch (K4).